Insert lat, long and capital for cities in python, Mysql

Question

I have 3 tables Countries, states and cities,cites table have name, and Foreign key for states, i added 3 more fields lat, lang and captial in cites tables. in cites table i have 46,000 around data.

I have a master Table contain around 4.3 m records, which contain all fields which i need in a single table. my code is given

import pandas as pd
import pymysql
import time
from Levenshtein import distance 
import csv
from functools import lru_cache

start_time = time.time()
connection=pymysql.connect(
    host="localhost",
    user="admin",
    password="Adxxxxx3",
    port=3306,
    db="rixxxx")

mycursor = connection.cursor()

mycursor.execute("SET FOREIGN_KEY_CHECKS=0")


mycursor.execute("SELECT ci.name as city_Name, ci.id as city_id, s.name as state_name, s.id as state_id, co.name as country_name, co.id as country_id FROM countrycap_states s inner join countrycap_cities ci on ci.state_id = s.id inner join countrycap_countries co on co.id = s.country_id ORDER BY `country_name` ASC ")
count_val = mycursor.fetchall()
with open('zzzzcities_unfilled.csv', 'w', encoding='UTF8') as f:
    for old_data in count_val:
        try:
            query_main_simp = "SELECT country, state, city,capital, latitude,longitude FROM `countrycap_simplecountry` where country = '{0}' and state = '{1}' and city = '{2}'".format(old_data[4], old_data[2], old_data[0])
            mycursor.execute(query_main_simp)
            ins_data = mycursor.fetchall()[0]
            # print(ins_data[3])
            if (ins_data[3] == 'admin') or (ins_data[3] == 'primary'):
                in_ss ="UPDATE countrycap_cities w JOIN countrycap_states x on w.state_id=x.id JOIN countrycap_countries co on co.id=x.country_id SET w.latitude = {0}, w.longitude = {1}, w.capital_city_admin = '{2}' WHERE w.name='{3}' and co.name='{4}' and x.name ='{5}'".format(ins_data[4],ins_data[5],ins_data[3],ins_data[2],ins_data[0],ins_data[1])
                mycursor.execute(in_ss)
                # print(in_ss)
                connection.commit()

            elif (ins_data[3] == 'minor') or (ins_data[3] == ''):
                in_ss ="UPDATE countrycap_cities w JOIN countrycap_states x on w.state_id=x.id JOIN countrycap_countries co on co.id=x.country_id SET w.latitude = {0}, w.longitude = {1} WHERE w.name='{2}' and co.name='{3}' and x.name ='{4}'".format(ins_data[4],ins_data[5],ins_data[2],ins_data[0],ins_data[1])
                mycursor.execute(in_ss)
                # print(in_ss)
                connection.commit()

        except Exception as e:
            writer = csv.writer(f)
            writer.writerow(old_data)

print("--- %s seconds ---" % (time.time() - start_time))

This Script takes hours(5-6) to complete task, i want make it quick in minutes. i have to filled lat and long for 46,000 only, what is best possible strategy to make script fast.

Thanks for your time.

Here i'm attaching schema for related table, country, state and city and Simple map country from where i have to fetch lat, long.enter image description here

It would be simpler to understand an SQL-related question if you post your schema(s). See [this checklist](https://meta.stackoverflow.com/questions/271055/tips-for-asking-a-good-structured-query-language-sql-question). — MyICQ, Sep 12 '22 at 06:32
Have you heard of Prepared Statements? Prepare the queries Once and execute them many times with new data each time. That would say 46k network round trips to compile the same statement again and again and again — RiggsFolly, Sep 12 '22 at 07:27
Show us a few lines of the source data and the desired results for the copying. I suspect one or two SQL statements would suffice, especially if you have adequate indexes. — Rick James, Sep 14 '22 at 15:11
i indexes desired fields so it make query fast, i acheved through indexing. — deepak, Sep 14 '22 at 16:10

Rick James · Answer 1 · 2022-09-14T15:10:13.720

Load any csv file using LOAD DATA. This will take minutes, maybe less.
In the LOAD necessary use @variables for some simple transformations as you do the load.
Write the rest of the necessary transforms using SQL. For example, the UPDATE to set all the capitals can probably be a single statement, no looping.
All the work can probably be done without any Python code.
Design the PRIMARY KEY for each table early; adding or changing it later is somewhat costly.
Delay adding INDEXes and/or FOREIGN KEYs, but do add them before they are needed.
See Mysql fastest technique for insert, replace, on duplicate of mass records for more discussion of LOAD + IODKU.

Insert lat, long and capital for cities in python, Mysql

1 Answers1